A Pacific Gas and Electric truck drives past a fire engine as San Francisco firefighters battle a fire on Geary Boulevard in San Francisco, Wednesday, Feb. 6, 2019. A gas explosion in a San Francisco neighborhood shot flames high into the air Wednesday and was burning four buildings as utility crews scrambled to shut off the flow of gas. Construction workers cut a natural gas line, San Francisco Fire Chief Joanne Hayes-White said. less

A Pacific Gas and Electric truck drives past a fire engine as San Francisco firefighters battle a fire on Geary Boulevard in San Francisco, Wednesday, Feb. 6, 2019. A gas explosion in a San Francisco ... more

A San Francisco police officer keeps watch near where an excavator sits near where firefighters work a gas line explosion and fire that burned several structures on Geary Blvd. in San Francisco, Calif., on Wednesday, February 6, 2019. The gas line was capped after about two hours burning uncontrolled. less

A San Francisco police officer keeps watch near where an excavator sits near where firefighters work a gas line explosion and fire that burned several structures on Geary Blvd. in San Francisco, Calif., on ... more

PG&amp;E officials dig up the ground to to reach a pipe as...photo-16887611.189755 - |ucfirst

Firefighters battle a fire following an explosion at Geary boulevard and Parker Avenue on Wednesday, Feb. 6, 2019, in San Francisco, Calif.

Firefighters battle a fire following an explosion at Geary boulevard and Parker Avenue on Wednesday, Feb. 6, 2019, in San Francisco, Calif.

Photo: Santiago Mejia/The Chronicle

Firefighters battle a fire following an explosion at Geary...photo-16886916.189755 - |ucfirst

Firefighters battle a fire following an explosion at Geary boulevard and Parker Avenue on Wednesday, Feb. 6, 2019, in San Francisco, Calif.

Firefighters battle a fire following an explosion at Geary boulevard and Parker Avenue on Wednesday, Feb. 6, 2019, in San Francisco, Calif.

Photo: Santiago Mejia/The Chronicle

Firefighters battle a fire following an explosion at Geary...photo-16886920.189755 - |ucfirst

A woman watches from a nearby restaurant as San Francisco firefighters work a gas line explosion and fire that burned several structures on Geary Blvd. in San Francisco, Calif., on Wednesday, February 6, 2019. The gas line was capped after about two hours burning uncontrolled. less

A woman watches from a nearby restaurant as San Francisco firefighters work a gas line explosion and fire that burned several structures on Geary Blvd. in San Francisco, Calif., on Wednesday, February 6, 2019. ... more

San Francisco firefighters work a gas line explosion and fire that burned several structures on Geary Blvd. in San Francisco, Calif., on Wednesday, February 6, 2019. The gas line was capped after about two hours burning uncontrolled. less

San Francisco firefighters work a gas line explosion and fire that burned several structures on Geary Blvd. in San Francisco, Calif., on Wednesday, February 6, 2019. The gas line was capped after about two ... more

San Francisco firefighters battle a fire triggered by an explosion...photo-16887047.189755 - |ucfirst

People watch as firefighters battle a fire following an explosion at Geary boulevard and Parker Avenue on Wednesday, Feb. 6, 2019, in San Francisco, Calif.

People watch as firefighters battle a fire following an explosion at Geary boulevard and Parker Avenue on Wednesday, Feb. 6, 2019, in San Francisco, Calif.

Photo: Santiago Mejia/The Chronicle

People watch as firefighters battle a fire following an explosion...photo-16886910.189755 - |ucfirst

San Francisco firefighters are battling a fire that may have started with a gas explosion at Geary Blvd. and Parker Ave. This photo shows a backhoe engulfed in flames next to the Hong Kong II restaurant.

San Francisco firefighters are battling a fire that may have started with a gas explosion at Geary Blvd. and Parker Ave. This photo shows a backhoe engulfed in flames next to the Hong Kong II restaurant.

Photo: Pierre-Yves Ricau / Twitter

San Francisco firefighters are battling a fire that may have...photo-16886598.189755 - |ucfirst

Firefighters battle a fire following an explosion at Geary boulevard and Parker Avenue on Wednesday, Feb. 6, 2019, in San Francisco, Calif.

Firefighters battle a fire following an explosion at Geary boulevard and Parker Avenue on Wednesday, Feb. 6, 2019, in San Francisco, Calif.

Photo: Santiago Mejia/The Chronicle

Firefighters battle a fire following an explosion at Geary...photo-16886925.189755 - |ucfirst

San Francisco Fire Dept. Chief Joanne Hayes-White answers questions from the media on Feb. 6 after a gas explosion at Parker and Geary streets. She said eight construction personnel working on underground fiberoptic lines likely breached a gas line, causing the explosion.

San Francisco Fire Dept. Chief Joanne Hayes-White answers questions from the media on Feb. 6 after a gas explosion at Parker and Geary streets. She said eight construction personnel working on underground

San Francisco firefighters are responding to a report of fire in the Inner Richmond.

San Francisco firefighters are responding to a report of fire in the Inner Richmond.

Photo: KTVU

San Francisco firefighters are responding to a report of fire in...photo-16886585.189755 - |ucfirst

San Francisco firefighters work a gas line explosion and fire that burned several structures on Geary Blvd. in San Francisco, Calif., on Wednesday, February 6, 2019. The gas line was capped after about two hours burning uncontrolled. less

San Francisco firefighters work a gas line explosion and fire that burned several structures on Geary Blvd. in San Francisco, Calif., on Wednesday, February 6, 2019. The gas line was capped after about two ... more

San Francisco firefighters work a gas line explosion and fire that...photo-16887715.189755 - |ucfirst

Two women watch the fire burn from a Red Cross station at Mels Diner as San Francisco firefighters work a gas line explosion and fire that burned several structures on Geary Blvd. in San Francisco, Calif., on Wednesday, February 6, 2019. The gas line was capped after about two hours burning uncontrolled. less

Two women watch the fire burn from a Red Cross station at Mels Diner as San Francisco firefighters work a gas line explosion and fire that burned several structures on Geary Blvd. in San Francisco, Calif., on ... more